In general, a fabrication process for a semiconductor device such as a flat panel display device and a solar cell includes repetition of a step of depositing a thin film, a photolithographic step of patterning a photoresist (PR) layer and a step of etching the thin film for a pattern. The deposition step and the etch step may be performed in a chamber of an apparatus having a reaction space separated from exterior. For example, a cluster type apparatus including a load-lock chamber, a transfer chamber and a process chamber may be used for the deposition step and the etch step, and the load-lock chamber, the transfer chamber and the process chamber may have a vacuum state during the deposition step and the etch step. Specifically, since a substrate is inputted from an exterior having an atmospheric state into the load-lock chamber and the substrate is transferred from the load-lock chamber to the transfer chamber having a vacuum state, the load-lock chamber alternately have the atmospheric state and the vacuum state.
FIG. 1 is a view showing a cluster type apparatus according to the related art.
In FIG. 1, a cluster type apparatus 10 includes a substrate loader/unloader 18, a load-lock chamber 12, a transfer chamber 14 and a plurality of process chambers 16. A plurality of substrates 20 are inputted into the substrate loader/unloader 18 for a process, and the plurality of substrates 20 are outputted from the substrate loader/unloader 18 after finishing the process. The load-lock chamber 12 is disposed between the substrate loader/unloader 18 and the transfer chamber 14. Accordingly, the plurality of substrates 20 are transferred from the substrate loader/unloader 18 to the transfer chamber 14 through the load-lock chamber 12. The substrate loader/unloader 18 includes a first robot 24 for transferring the plurality of substrates 20 from the substrate loader/unloader 18 to the load-lock chamber 12, and the transfer chamber 14 includes a second robot 22 for transferring the plurality of substrates 20 from the load-lock chamber 12 to the plurality of process chambers 16.
FIG. 2 is an exploded perspective view showing a load-lock chamber of a cluster type apparatus according to the related art.
In FIG. 2, a load-lock chamber 12 includes a chamber body 28 and a chamber lid 29. The chamber body 28 includes first to fourth sidewalls 30, 32, 34 and 36. The first and second sidewalls 30 and 32 have first and second slot valves 31 and 33, respectively, for substrate transfer, and the third and fourth sidewalls 34 and 35 are disposed between the first and second sidewalls 30 and 32. As a result, the substrate 20 (of FIG. 1) is inputted from the substrate loader/unloader 18 (of FIG. 1) to the load-lock chamber 12 through the first slot valve 31, and the substrate 20 is outputted from the load-lock chamber 12 to the transfer chamber 14 (of FIG. 1) through the second slot valve 33. Each of third and fourth sidewalls 36 and 38 has a view port 38 for inspecting the inside of the load-lock chamber 12. The view port 38 may be opened for inspection and may be closed after inspection. The chamber body 28 and the chamber lid 29 may be formed of a metallic material such as aluminum (Al).
Further, a diffuser 40 is formed on one of the third and fourth sidewalls 36 and 38. The load-lock chamber 12 of a vacuum state is ventilated by a gas injected through the diffuser 40 to have an atmospheric state. For example, a nitrogen gas (N2) may be diffused into the load-lock chamber 12 through the diffuser 40. A vacuum pump (not shown) is connected to the load-lock chamber 12 for obtaining the vacuum state. In addition, a plurality of substrate supporters 42 spaced apart from each other are formed in the load-lock chamber 12. The substrate 20 is loaded on the plurality of substrate supporters 42 and arms of the second robot 22 of the transfer chamber 14 are inserted into the spaces between the substrate supporters 42. Accordingly, the substrate 20 is transferred from the load-lock chamber 12 to the transfer chamber 14 using the second robot 22 through the second slot valve 33. The plurality of substrate supporters 42 may include a heating means (not shown) for heating up the substrate 20.
The load-lock chamber 12 is evacuated for conversion from the atmospheric state to the vacuum state and is ventilated for conversion from the vacuum state to the atmospheric state. Accordingly, evacuation and ventilation are repeatedly performed for the load-lock chamber 12. In addition, the substrate 20 is heated up to have a process temperature in the load-lock chamber 12. Since the load-lock chamber 12 is formed of a metallic material such as aluminum (Al) having a relatively low strength, the chamber body 28 and the chamber lid 29 of the load-lock chamber 12 may be deformed due to the repetition of evacuation and ventilation under a relatively high temperature. As a result, the lifetime of the load-lock chamber 12 is reduced.